Semiconductor element, semiconductor device, and method for manufacturing semiconductor element

ABSTRACT

A semiconductor chip of the present invention is so arranged that a front face on which an element circuit is formed has electrode pads and a side face and a back face are coated with a shielding layer for shielding electromagnetic waves. With this, it is possible to provide a semiconductor element capable of being easily manufactured into a smaller semiconductor device compared with a conventional semiconductor device equipped with a shielding cap; a semiconductor device; and a method for manufacturing a semiconductor element.

FIELD OF THE INVENTION

[0001] The present invention relates to a semiconductor element having ashielding structure, a semiconductor device, and a method formanufacturing a semiconductor element.

BACKGROUND OF THE INVENTION

[0002] In these years, in accordance with the miniaturization ofelectronic equipments, there is a growing demand for electronic partssuch as a semiconductor device that can realize miniaturization andhigh-density packaging. In response to this demand for higher density,it is required to mount both analog and digital circuits together, ordevices having high clock frequency together. In these cases, noise isknown to generate among the closely located devices due toelectromagnetic waves.

[0003] In order to shield a semiconductor device or module that issusceptible to electromagnetic waves from a semiconductor device ormodule that considerably generates electromagnetic waves, a wholesemiconductor device or module is generally covered with a metal capcalled a shielding cap, etc.

[0004] As an example of this kind of semiconductor device, JapaneseUnexamined Patent Publication No. 256412/1998 (Tokukaihei 10-256412;published on Sep. 25, 1998) proposes a semiconductor device having astructure as shown in FIG. 19, together with its manufacturing method.

[0005] As shown in FIG. 19, the above semiconductor device is arrangedas follows. A semiconductor device main body 110 is so arranged that asemiconductor chip (semiconductor element) 102 is mounted on arectangular wiring substrate 101, and a protruded external connectingterminal 103 is provided on a back face of the wiring substrate 101.Then, the semiconductor device main body 110 is covered with a shieldingcap 121 having a rectangular parallelepiped shape with an open bottomface so that top and side faces of the semiconductor device main body110 are covered, and the shielding cap 121 is adhered to thesemiconductor device main body 110 with an adhesive agent 122.

[0006] On a front side of the semiconductor chip 102, an element circuit(not shown) is formed. The semiconductor chip 102 is mounted on thewiring substrate 101 either using an upset so as to be electricallyconnected to the wiring substrate 101 by a bonding wire 104, or using adownset by a flip chip connecting method. The mounted semiconductor chip102 is covered with sealing resin 105.

[0007] The material of the shielding cap 121 is a gold-plated ortin-plated metal such as copper, or nickel silver. The dimensions of astoring section of the shielding cap 121 in a horizontal direction is alittle larger than the size of the wiring substrate 101 so as to fullycover the semiconductor device main body 110. Further, inside the sidefaces of the shielding cap 121 is provided with a pressed protrusion 123for fixing the wiring substrate 101.

[0008] A method for manufacturing the above-described semiconductordevice will be explained as follows. After the semiconductor device mainbody 110 is formed, the adhesive agent 122 is thickly put on the sealingresin 105 on the semiconductor device main body 110 using a dispensenozzle (not shown); the shielding cap 121 attached by attachingconveying means (not shown) is put on from above and pushed into a fixedposition; and then curing treatment is applied.

[0009] However, the conventional semiconductor device and theconventional method for manufacturing the semiconductor element have thefollowing problems.

[0010] (A) The whole semiconductor device becomes very large, becausethe semiconductor device main body 110 larger than the chip size isfurther covered with the shielding cap 121.

[0011] (B) It is required to prepare the shielding cap 121 variously inaccordance with the semiconductor device main bodies 110 in differentsizes.

[0012] (C) The application is limited to an area array such as a BGA(Ball Grid Array).

[0013] (D) The assembling steps become complicated, because, after thesemiconductor device main body 110 is assembled, each semiconductordevice main body 110 has to undergo the steps of dispensing the adhesiveagent 122, covering with the shielding cap 121 that is press-molded andsubjected to plating, etc., and curing the adhesive agent 122.

[0014] (E) It is difficult to shield a back face (external connectingterminal side) of the semiconductor device.

SUMMARY OF THE INVENTION

[0015] An object of the present invention is to provide a semiconductorelement capable of being easily manufactured into a smallersemiconductor device compared with a conventional semiconductor deviceequipped with a shielding cap; a semiconductor device; and a method formanufacturing a semiconductor element.

[0016] In order to attain the foregoing object, a semiconductor elementof the present invention, whose front face on which an element circuitis formed has electrode pads and whose side face is provided between thefront face and a back face on a back side of the front face, ischaracterized in that the side face and the back face are coated with ashielding layer for shielding electromagnetic waves.

[0017] Namely, the conventional semiconductor device has a problem suchthat the entire size of the semiconductor device becomes very large,because the semiconductor device is covered with a shielding cap.

[0018] With the present invention, however, the side and back faces ofthe semiconductor element are coated with the shielding layer forshielding electromagnetic waves. In other words, the semiconductorelement is directly coated with the shielding layer.

[0019] As a result, it becomes possible to provide a semiconductorelement capable of being easily manufactured into a smallersemiconductor device compared with the conventional semiconductor deviceequipped with a shielding cap. This also eliminates the need formanufacturing the shielding cap variously in accordance with differentshapes and sizes of the semiconductor devices, so that a pressing moldbecomes unnecessary. This obviates the complexities of manufacturing andmanaging various kinds of shielding caps.

[0020] In order to attain the foregoing object, a semiconductor deviceof the present invention is characterized in that an external connectingterminal is formed on a semiconductor element, whose front face on whichan element circuit is formed has electrode pads and whose side face isprovided between the front face and a back face on a back side of thefront face, the side face and the back face being coated with ashielding layer for shielding electromagnetic waves.

[0021] With this arrangement, the semiconductor device is so arrangedthat an external connecting terminal is formed on the above-describedsemiconductor element. Namely, the semiconductor device is composed of asemiconductor element of the electromagnetic wave shielding type asarranged above.

[0022] With this, it becomes possible to provide a smaller semiconductordevice compared with the conventional semiconductor device equipped witha shielding cap. This also eliminates the need for manufacturing theshielding cap variously in accordance with different shapes and sizes ofthe semiconductor devices, so that a pressing mold becomes unnecessary.This obviates the complexities of manufacturing and managing variouskinds of shielding caps.

[0023] In order to attain the foregoing object, a method formanufacturing a semiconductor element of the present invention ischaracterized so as to have the steps of (1) fixing a sheet or platematerial on a front face of a wafer on which an element circuit,electrode pads, and a cutting line that is formed so as to surround theelement circuit and the electrode pads are formed, respectively; (2)forming a groove along the cutting line on a back face which is on aback side of the wafer front face; (3) forming a shielding layer so asto shield electromagnetic waves on the wafer back face having the grooveand on a concave portion of the groove; and (4) removing the sheet orplate material fixed on the wafer front face, the steps (1) through (4)being processed in this order.

[0024] With this method, when manufacturing the semiconductor element,first, (1) a sheet or plate material is fixed on a front face of a waferon which an element circuit, electrode pads, and a cutting line that isformed so as to surround the element circuit and the electrode pads areformed, respectively. Next, (2) a groove is formed along the cuttingline on a back face which is on a back side of the wafer front face.Then, (3) a shielding layer for shielding electromagnetic waves isformed on the wafer back face having the groove and on a concave portionof the groove. After this, (4) the sheet or plate material fixed on thewafer front face is removed.

[0025] With this, it is possible to provide a method for manufacturing asemiconductor element whose back and side faces have the electromagneticwave shielding structure.

[0026] For a fuller understanding of the nature and advantages of theinvention, reference should be made to the ensuing detailed descriptiontaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is a cross-sectional view showing an embodiment of asemiconductor chip of the present invention.

[0028]FIG. 2 is a cross-sectional view showing a semiconductor chipwhose side faces have a taper.

[0029] FIGS. 3(a) through 3(d) are cross-sectional views showingmanufacturing steps of the semiconductor chip.

[0030] FIGS. 4(a) through 4(c) show a state where a wafer is equippedwith a jig in the manufacturing steps. FIG. 4(a) is the front view, FIG.4(b) is the plan view, and FIG. 4(c) is the bottom plan view.

[0031]FIG. 5(a) is a front view showing a blade used in themanufacturing steps. FIG. 5(b) is a side view showing the blade.

[0032] FIGS. 6(a) and 6(b) are cross-sectional views showingmanufacturing steps of the semiconductor chip after those shown in FIGS.3(a) through 3(d).

[0033] FIGS. 7(a) through 7(c) are cross-sectional views each showinghow a shielding layer is formed when a shielding layer of a conductivematerial is formed only by sputtering. FIG. 7(a) shows a case where avertical groove is formed. FIG. 7(b) shows a case where a groove isformed on a back face of a wafer whose thickness is reduced by back facepolishing. FIG. 7(c) shows a case where a taper is formed on side facesof a wafer.

[0034] FIGS. 8(a) through 8(c) are cross-sectional views each showinghow a shielding layer is formed when a shielding layer of a conductivematerial is formed by sputtering and subsequent electrolytic plating.FIG. 8(a) shows a case where a vertical groove is formed. FIG. 8(b)shows a case where a groove is formed on a back face of a wafer whosethickness is reduced by back face polishing. FIG. 8(c) shows a casewhere a taper is formed on side faces of a wafer.

[0035] FIGS. 9(a) through 9(c) are cross-sectional views each showinghow a shielding layer is formed when a shielding layer is made of aresin sheet as an example of an electromagnetic wave absorbing material.FIG. 9(a) shows a case where a vertical groove is formed. FIG. 9(b)shows a case where a groove is formed on a back face of a wafer whosethickness is reduced by back face polishing. FIG. 9(c) shows a casewhere a taper is formed on side faces of a wafer.

[0036]FIG. 10 is a cross-sectional view showing another embodiment ofthe semiconductor chip of the present invention.

[0037] FIGS. 11(a) through 11(e) are cross-sectional views showingmanufacturing steps of the above semiconductor chip.

[0038] FIGS. 12(a) through 12(c) are cross-sectional views showingmanufacturing steps of the above semiconductor chip after those shown inFIGS. 11(a) through 11(e).

[0039] FIGS. 13(a) and 13(b) are cross-sectional views showingmanufacturing steps of the above semiconductor chip after those shown inFIGS. 12(a) through 12(c).

[0040]FIG. 14 is a cross-sectional view showing a further embodiment ofthe semiconductor chip of the present invention.

[0041]FIG. 15 is a cross-sectional view showing another example of theabove semiconductor chip.

[0042] FIGS. 16(a) through 16(d) are cross-sectional views showingmanufacturing steps of the above semiconductor chip.

[0043]FIG. 17 is a cross-sectional view showing a semiconductor deviceof the present invention.

[0044]FIG. 18 is a cross-sectional view showing another example of theabove semiconductor device.

[0045]FIG. 19 is a cross-sectional view showing a conventionalsemiconductor device.

DESCRIPTION OF THE EMBODIMENTS

[0046] [First Embodiment]

[0047] The following will explain an embodiment of the present inventionwith reference to FIGS. 1 through 9(a) to 9(c).

[0048] As shown in FIG. 1, a semiconductor chip (semiconductor element)1 of the present embodiment is a semiconductor chip of a shielding type.The semiconductor chip 1 is provided with an element circuit (not shown)on a front face side. Further, a chip front face (element front face) 1a of the semiconductor chip 1 is provided with a passivation film 3having an opening 3 a only on a portion of an electrode pad 2. Thepassivation film 3 is composed of an inorganic material such as SiO₂ andSiN, or an organic material such as polyimide. Two or more passivationfilms 3 may be provided. Note that, the manufacturing process of asemiconductor device generally consists of a wafer process called as afront-end process and an assembling process (packaging) called as aback-end process. The passivation film 3 is generally formed in a laststep of the wafer process, because the passivation film 3 is formed toprotect the semiconductor element from thermal or physical stressapplied in the back-end process, etc.

[0049] In the present embodiment, a chip back face (element back face) 1b and a chip side face (element side face) 1 c of the semiconductor chip1 are covered with a shielding layer 4. The shielding layer 4 iscomposed of a conductive material such as Au. As a foundation layer ofthe shielding layer 4, an insulating layer (not shown) is formed tosurely insulate the shielding layer 4 from a chip main body 10. Themethod for forming the insulating layer may be various methods such as amethod of applying resin varnish, but a CVD (Chemical Vapor Deposition)method, which is capable of uniformly forming a thin film, is used toform an oxide film here.

[0050] Note that, the above-described semiconductor chip 1 has arectangular cross-sectional shape, but the cross-sectional shape of thesemiconductor chip 1 is not limited to this. For example, as shown inFIG. 2, the chip side face 1 c of the semiconductor chip 1 may have ataper. Namely, the chip back face 1 b has a smaller area than the chipfront face 1 a on which the element circuit is formed.

[0051] With this tapered shape, when the shielding layer 4 is formed byvapor-phase or liquid-phase growth, the shielding layer 4 can be formedto have a uniform thickness on the chip back face 1 b and the chip sideface 1 c of the semiconductor chip 1. Namely, it is possible to preventthe shielding layer 4 from being partly thinned or punctured on the chipside face 1 c of the semiconductor chip 1. Further, the insulating layer(not shown) as the foundation layer of the shielding layer 4 also can beformed to have a uniform thickness on the back face and the side face,thereby effectively maintaining the uniformity of the film.

[0052] Next, a method for manufacturing the semiconductor chip 1 asarranged above will be explained with reference to FIGS. 3(a) through3(d).

[0053] First, as shown in FIG. 3(a), prepared is a wafer 20 whose frontface is provided with the element circuit (not shown), the electrodepads 2, and the passivation film 3 which is formed on a portion exceptthe element circuit, the electrode pads 2, and scribe lines (cuttinglines) 21. Here, the scribe line 21 is a lined area that is to be cut ina later step in which the wafer 20 is separated into individual pieces.

[0054] Next, as shown in FIG. 3(b), a wafer front face 20 a of the wafer20 is fixed on a jig 31. The jig 31 may be made of any material having asmooth surface and sufficient tolerance for later steps. For example,the material includes a metal material such as stainless steel andaluminum, a plate material such as glass and a silicon wafer, and atensioned heat-resistant resin sheet of polyimide such as upilex. Notethat, when using the tensioned heat-resistant resin sheet, it ispreferable to use it after attached to a ring jig, etc., that is used insteps such as a dicing step for cutting the wafer into individualpieces.

[0055] The wafer 20 can be fixed on the above-described material when anadhesive agent is applied on the above-described material. When theadhesive agent has a glass transition point Tg of not less than 200° C.,for example, the adhesive agent has tolerance for later steps. Further,since the later steps include a peeling process, it is preferable to usean adhesive agent whose adhesion can be lowered by UV irradiation,chemicals such as acetone, heating, etc.

[0056] In the present embodiment, the jig 31 made of glass is used, anda thermoplastic adhesive agent made of polyimide is used as the adhesiveagent. Further, the adhesive agent is used by being applied on the jig31. Generally, this kind of adhesive agent is used for secure fixing bycompression bonding at a high temperature of not less than 350° C.However, in this case, the jig is only fixed so as not to be peeledduring the steps, so that thermo compression bonding is lightly carriedout at a temperature of approximately 250° C. This adhesion enablesseparation at a surface of the adhesive agent in the later peeling step.

[0057] Further, after the glass jig 31 larger than the wafer 20 ispasted on the wafer 20, by marking scribe line positions on an exceedingportion of the glass surface, the wafer 20 can be subjected to dicing.Note that, when the jig 31 is not made of a transparent material, bymarking the scribe line positions on a back face of the wafer 20 using alaser, etc., the wafer 20 can be subjected to dicing.

[0058] Specifically, as shown in FIG. 4(a), the glass jig (sheet orplate material) 31, which is a little larger than the wafer 20, ispasted on the wafer 20 on a side of the element circuit formed on thewafer front face 20 a. The scribe line positions are marked on the frontsurface of the jig 31 (in FIG. 4(a), from above of the sheet planarsurface), as shown in FIG. 4(b). Note that, only a peripheral portion ofthe jig 31 may be marked. When the marked jig 31, etc. is seen from theback side of the wafer 20 (in FIG. 4(a), from below of the sheet planarsurface), the marking is visible because the jig 31 is made oftransparent glass. As a result, using the marking as a reference, thewafer 20 can be subjected to dicing from the back face.

[0059] Following this, as shown in FIG. 3(c), the wafer 20 is subjectedto dicing at the scribe lines 21 using a blade 32. Note that, a bladefor dicing is generally disk-shaped and has a uniform thickness ofapproximately 50 μm. However, since the blade having a uniform thicknesscreates vertical cut surfaces, it is difficult to achieve the uniformthickness of the shielding layer 4, etc. in a next step. As a method toprevent this, the back face of the wafer 20 may be polished so that thewafer 20 has the thickness of not more than about 200 μm, for example,thereby achieving a certain degree of uniformity of the film. Namely,wafer thickness is generally predetermined. More specifically, a 4-inchwafer has a thickness of 525 μm, a 6-inch wafer has a thickness of 625μm, and an 8-inch wafer has a thickness of 725 μm. Therefore, bypolishing the wafer to have a thickness of not more than about 200 μm,it is possible to maintain a certain degree of uniformity of the film.

[0060] On the other hand, as another method to maintain the uniformthickness of the shielding layer 4, etc., a circular blade 32 havingdifferent thicknesses at outer and inner circumferential portions isused in the present embodiment, as shown in FIGS. 5(a) and 5(b). Theouter circumferential portion of the blade 32 has a thickness of 50 μm,whereas an inner circumferential portion that is 800 μm radially insidethe outer circumferential portion has a thickness of 980 μm. By usingthis blade 32, when the circular blade 32 rotates on a rotation axis soas to form a groove on an object, a taper is formed on the chip sideface 1 c of the semiconductor chip 1 that is separated from the wafer20, allowing the chip front face 1 a to have a larger area than the chipback face 1 b. Further, in the present embodiment, by using this blade32, it is possible to maintain the uniform thickness of the shieldinglayer 4, etc., as later described. Note that, the taper is formed so asto have a point angle of 60° here. However, as the angle becomes larger,it becomes easier to form a uniform film such as the shielding layer 4in a later step.

[0061] Further, other methods to form the taper include wet etching,laser irradiation at different angles, etc.

[0062] Next, as shown in FIG. 3(d), the insulating film (not shown) asthe foundation layer of the shielding layer 4 is formed by aphoto-assisted CVD method. Note that, various methods for forming theinsulating film may be employed. For example, sheet resin such aspolyimide may be pasted on so as to wrap the semiconductor chip 1, whilebeing heated under reduced pressure with respect to the jig 31. Employedhere is the CVD method, which can uniformly form a thin insulating film.There are several types in the CVD method, but it is preferable to usethe photo-assisted CVD, which can form an oxide film at a relatively lowtemperature. Using SiH₄—N₂O as a reactive material, the oxide film isformed.

[0063] Next, the shielding layer 4 is formed in such a manner that Au isformed to have a thickness of approximately 1 μm by sputtering. Theshielding layer 4 may be formed thicker by electrolytic Au plating ifnecessary. When the electrolytic plating is applied, the film formed bythe sputtering may have a thickness of only about 0.1 μm in view of atime for forming the film. Further, since Au is expensive, other metalmaterials such as Cu may be used. In this case, Cu is formed bysputtering. Note that, when it is necessary to form Cu thicker, variousmethods may be employed such that Cu is further formed by electrolyticplating. Further, other than metal, a material that absorbselectromagnetic waves may be used. For example, when a resin sheetcontaining powder ferrite is heated under reduced pressure with respectto the jig 31, the resin sheet fits and adheres to the indented surface.In this method, by polishing the chip back face 1 b of the semiconductorchip 1 so that the wafer has a thickness of not more than about 200 μm,or by forming a taper on the chip side face 1 c, it is possible toprevent the inclusion of bubbles in spite of the indented surface.Further, ferrite particles and resin containing ferrite particlesgenerally have an insulating property, thereby eliminating the need forthe insulating layer as the foundation layer.

[0064] A peeling tool 35 is assembled in such a manner that, forobtaining tension, a ring jig 34 is pasted on an adhesive sheet 33 whichis a dicing sheet. Next, as shown in FIG. 6(a), the adhesive sheet 33 ofthe peeling tool 35 is pasted on the shielding layer 4 on the back sideof the semiconductor chip 1.

[0065] Next, as shown in FIG. 6(b), the jig 31 that is lightly fixed ispeeled, and a curved jig 36 having a curved surface is pressed on, so asto separate the respective semiconductor chips 1.

[0066] As another method, the semiconductor chips 1 that are connectedvia the shielding layer 4 may be separated by another dicing, afterpeeling the jig 31. Here, a disk-shaped blade for dicing having auniform thickness is used. This blade for dicing preferably has a thinthickness, and may have a thickness of approximately 30 μm, for example.

[0067] The following will explain how the shielding layer 4 is formed onthe side faces of the semiconductor chip 1 when the shielding layer 4 isformed with the above-described method. First, a case will be explainedwhere the shielding layer 4 of a conductive material is formed only bysputtering.

[0068] As shown in FIG. 7(a), when the groove is formed on the back faceof the wafer 20 without subjected to the back face polishing, asputtering film is formed thinner on side faces of the groove than onthe wafer back face because the groove is deep. In contrast, as shown inFIG. 7(b), when the groove is formed on the back face of the wafer 20whose thickness is reduced after subjected to the back face polishing,the sputtering film is uniformly formed on the side faces of the groovebecause the groove is not deep. Further, when the taper is formed at thegroove, as shown in FIG. 7(c), the sputtering film is uniformly formedon the side faces of the groove as on the back face of the wafer 20.

[0069] Next, a case will be explained where the shielding layer 4 ismade of a conductive material and is formed by sputtering and subsequentelectrolytic plating.

[0070] First, as shown in FIG. 8(a), when the groove is formed on theback face of the wafer 20 without subjected to the back face polishing,a plated film is formed thinner on side faces of the groove than on thewafer back face, because the plating liquid does not circulate wellinside the deep groove. Further, since the electrolyzation tends toconcentrate at edge portions, the plating film swells at the edgeportions, thereby causing short-circuiting.

[0071] In contrast, as shown in FIG. 8(b), when the groove is formed onthe back face of the wafer 20 that is subjected to the back facepolishing, the plating film is uniformly formed on the side faces of thegroove, because the plating liquid is easily supplied inside the shallowgroove, thereby achieving a film thickness almost the same as on theback face of the wafer 20.

[0072] Next, when the taper is formed at the groove, as shown in FIG.8(c), the plating film is uniformly formed on the side faces of thegroove, because the plating liquid is easily supplied inside the groove,thereby achieving a film thickness almost the same as on the back faceof the wafer 20.

[0073] Next, a case will be explained where the shielding layer 4 ismade of a resin sheet containing powder ferrite as an example of theelectromagnetic wave absorbing material as shown in Embodiment 3 aslater described.

[0074] First, as shown in FIG. 9(a), when the groove is formed on theback face of the wafer 20 without subjected to the back face polishing,the resin sheet tries to fit the indented surface by being heated underreduced pressure between the resin sheet containing powder ferrite andthe wafer 20, but the resin sheet has difficulty in fitting in a bottomportion of the groove because the groove is deep.

[0075] In contrast, as shown in FIG. 9(b), when the groove is formed onthe back face of the wafer 20 whose thickness is reduced after subjectedto the back face polishing, by heating under reduced pressure, the resinsheet containing powder ferrite easily fits in the bottom portion of thegroove because the groove is not deep.

[0076] Further, when the taper is formed at the groove, as shown in FIG.9(c), the resin sheet containing powder ferrite easily fits in thebottom portion of the groove even if the wafer 20 is thick.

[0077] As described above, in the present embodiment, the chip side face1 c and the chip back face 1 b of the semiconductor chip 1 are coatedwith the shielding layer 4 which shields electromagnetic waves. Namely,the semiconductor chip 1 is directly coated with the shielding layer 4.

[0078] With this, it is possible to provide the semiconductor chip 1capable of being easily manufactured into a smaller semiconductor devicecompared with a conventional semiconductor device equipped with ashielding cap. This also eliminates the need for manufacturing theshielding cap variously in accordance with different shapes and sizes ofthe semiconductor devices, so that a pressing mold becomes unnecessary.This obviates the complexities of manufacturing and managing variouskinds of shielding caps.

[0079] Further, in the present embodiment, the chip back face 1 b of thesemiconductor chip 1 has a smaller area than the chip front face 1 a.Thus, when an insulating layer or the shielding layer 4 is formed on theback and side faces of the semiconductor chip 1, it is possible touniformly form the layer to have almost the same thickness on the backand side faces of the semiconductor chip 1.

[0080] Further, in the semiconductor chip 1 of the present embodiment,the shielding layer 4 is made of a conductive material. This preventsthe entrance of electromagnetic waves from the semiconductor chip 1 tothe outside or from the outside to the semiconductor chip 1, therebyreducing the effects of noise, etc. In addition to electromagneticwaves, the shielding layer 4 made of a conductive material also preventsthe transmission of light, thereby preventing a malfunction due to aphotovoltaic effect.

[0081] Further, a method for manufacturing the semiconductor chip 1 ofthe present embodiment is arranged so as to have the steps of (1) fixingthe jig 31 on the wafer front face 20 a on which the element circuit,the electrode pads 2, and the scribe lines 21 that are formed so as tosurround the element circuit and the electrode pads 2 are formed,respectively; (2) forming a groove along each of the scribe lines 21 ona wafer back face which is on a back side of the wafer front face 20 a;(3) forming the shielding layer 4 so as to shield electromagnetic waveson the wafer back face having the groove and on a concave portion of thegroove; and (4) removing the jig 31 fixed on the wafer front face 20 a.

[0082] With this, it is possible to provide a method for manufacturingthe semiconductor chip 1 whose back and side faces have theelectromagnetic wave shielding structure.

[0083] The method for manufacturing the semiconductor chip 1 of thepresent embodiment is so arranged that a taper is formed so that agroove has a wider width on a side of the back face than on a side ofthe front face, in the step of forming a groove along each of the scribelines 21 on the back face of the wafer.

[0084] With this, when an insulating layer or the shielding layer 4 isformed on the chip back face 1 b and the chip side face 1 c of thesemiconductor chip 1, the layer is uniformly formed to have almost thesame thickness on the chip back face 1 b and the chip side face 1 c.Thus, it is possible to provide a high-quality semiconductor chip 1 ofthe electromagnetic wave shielding type.

[0085] [Second Embodiment]

[0086] The following will explain another embodiment of the presentinvention with reference to FIGS. 10 through 13(a) and 13(b). For easeof explanation, members having the same functions as those shown in thedrawings pertaining to the first embodiment above will be given the samereference symbols, and explanation thereof will be omitted here.

[0087] A semiconductor chip (semiconductor element) of the presentembodiment is also a semiconductor chip of a shielding type. In thissemiconductor chip 50, the passivation film 3 is provided on a chipfront face 50 a that has an element circuit (not shown). The passivationfilm 3 has the opening 3 a only at a portion on the electrode pad 2.

[0088] In the present embodiment, the electrode pad 2 is electricallyconnected to one end of secondary wiring 51, and an insulating layer 52is formed thereon so as to have an opening 52 a to reveal an electrodepad 51 a formed with the secondary wiring 51. A taper is formed on achip side face 50 c of the semiconductor chip 50, and the shieldinglayer 4 is formed on a chip back face 50 b and on the chip side face 50c.

[0089] When the shielding layer 4 is made of a conductive material, aninsulating layer (not shown) is formed as the foundation layer. Theshielding layer 4 made of a conductive material is electricallyconnected via the secondary wiring 51 to the electrode pad 2 which is aground terminal.

[0090] Another end of the secondary wiring 51 is revealed at the opening52 a on the insulating layer 52. The secondary wiring 51 revealed at theopening 52 a on the insulating layer 52 is used for external electricalconnection. Note that, when the shielding layer 4 is made of anelectromagnetic wave absorbing material, there is no need to connect theground terminal with the shielding layer 4.

[0091] Next, a method for manufacturing the semiconductor chip 50 asarranged above will be explained with reference to FIGS. 11(a) through11(e), 12(a) through 12(c), 13(a), and 13(b).

[0092] First, as shown in FIG. 11(a), prepared is a wafer 20 whose frontface is provided with the element circuit (not shown), the electrodepads 2, and the passivation film 3 which is formed on a portion exceptthe element circuit, the electrode pads 2, and scribe lines 21.

[0093] Next, as shown in FIG. 11(b), after a metal thin film (not shown)is formed by sputtering, a resist 53 is formed to have an almost uniformthickness on an entire surface of the wafer front face 20 a on which theelement circuit is formed, and then photolithography is carried out soas to form an opening 53 a at a portion where the secondary wiring 51 isto be formed.

[0094] When the electrode pad 2 is made of Al, a first-layer metal thinfilm formed by the sputtering may be Ti, Ti—W, Cr, etc., which havefunctions of adhesion and barrier. Ti—W is used here. Further, when thesecondary wiring 51 is made of Cu, a second-layer metal thin film needsto be made of Cu. As described above, a material for the second-layermetal thin film needs to be selected in accordance with a material ofthe secondary wiring 51. Here, Cu is formed as the second-layer metalthin film, and then Cu, Ni, and Au are sequentially layered by anelectrolytic plating method on the opening 53 a of the resist 53,thereby forming the secondary wiring. The Cu wiring is used because itis more inexpensive compared with Au and it has good conductivity.

[0095] Further, as shown in FIG. 11(c), the Au is formed at theoutermost layer because of reasons such that it is capable of beingconnected to Au wire, etc., capable of being easily connected bysoldering, and capable of preventing surface oxidation. The Ni is formedbecause it can prevent the Cu from diffusing into the surface, and it isrequired for solder connection. As described above, the semiconductorchip can be connected in various forms, so that the semiconductor chipcan be mounted on and applied to various types of semiconductor devices.

[0096] Next, as shown in FIG. 11(d), after the secondary wiring 51 isformed, the resist 53 is separated. Generally, the resist 53 can beseparated easily by a solvent such as acetone. Then, the Cu and Ti—Wmetal thin films, which become unnecessary, are sequentially removed bywet etching using the secondary wiring 51 as a mask.

[0097] Next, as shown in FIG. 11(e), the insulating layer 52 is formedto protect the secondary wiring 51. The insulating layer 52 is formed insuch a method that photosensitive resin varnish is applied and formedinto a film, and then photolithography is carried out for patterning.The patterning forms an opening at a desired portion on the scribe lines21 and on the secondary wiring 51, and then heat treatment is appliedfor curing.

[0098] The following steps are carried out in the same manner as inFirst Embodiment. Namely, as shown in FIG. 12(a), on a side of anelement formed surface on which the secondary wiring 51 and theinsulating layer 52 are formed, the wafer 20 is fixed on the jig 31. Thejig 31 is made of a material having a smooth surface and sufficienttolerance for later steps. Here, a plate glass jig 31 is used. On asurface of the jig 31, a thermoplastic adhesive agent of polyimidehaving a glass transition point Tg of not less than 200° C., forexample, is applied and formed so as to uniformly have a thin thickness.The jig 31 is only fixed on the wafer 20 so as not to be peeled duringthe steps, so that thermo compression bonding is lightly carried out ata temperature of approximately 250° C. This adhesion enables separationat a surface of the adhesive agent in the later peeling step.

[0099] Following this, as shown in FIG. 12(b), grooves are formed bydicing on a wafer back face 20 b of the wafer 20. Note that, a circularblade 32 having different thicknesses at outer and inner circumferentialportions is used here. The outer circumferential portion of the blade 32has a thickness of 50 μm, whereas an inner circumferential portion thatis 800 μm radially inside the outer circumferential portion has athickness of 980 μm. By using this blade 32, a taper is formed on a chipside face 50 c of a semiconductor chip 50 that is separated from thewafer 20, allowing a chip front face 50 a to have a larger area than achip back face 50 b.

[0100] Next, as shown in FIG. 12(c), the insulating layer (not shown) isformed by a photo-assisted CVD method as the foundation layer (notshown) of the shielding layer 4. Using SiH₄—N₂O as a reactive material,the semiconductor chip 50 is heated at approximately 200° C. in achamber and irradiated by a mercury lamp, thereby forming the film.Next, the shielding layer 4 is formed in such a manner that Au is formedto have a thickness of approximately 1 μm by sputtering. The shieldinglayer 4 may be formed thicker by electrolytic Au plating if necessary.Further, the shielding layer 4 may be formed with a conductive materialother than Au and, for example, other metal materials such as Cu. Inthis case, Cu is formed by sputtering. Note that, when it is necessaryto form Cu thicker, various methods may be employed such that Cu isfurther formed by electrolytic plating. Further, other than metal, amaterial that absorbs electromagnetic waves may be used. For example,when a resin sheet containing powder ferrite is heated under reducedpressure with respect to the jig 31, the resin sheet would fit andadhere to the chip back face 50 b and the chip side face 50 c of thesemiconductor chip 50. In this case, ferrite and resin containingferrite particles have an insulating property, thereby eliminating theneed for the insulating layer as the foundation layer. Further, there isno need to connect the secondary wiring 51 with the shielding layer 4.

[0101] A peeling tool 35 is made in such a manner that, for obtainingtension, a ring jig 34 is pasted on an adhesive sheet 33 which is adicing sheet. Next, as shown in FIG. 13(a), the adhesive sheet 33 of thepeeling tool 35 is pasted on the shielding layer 4 on the back side ofthe semiconductor chip 50.

[0102] Next, as shown in FIG. 13(b), the jig 31 that is lightly fixed ispeeled, and a curved jig 36 having a curved surface is pressed on, so asto separate the respective semiconductor chips 50.

[0103] As described above, in the semiconductor chip 50 of the presentembodiment, a secondary wiring 51 is further provided on the wafer frontface 20 a so as to be electrically connected to the electrode pads 2.Further, the insulating layer 52 is provided on the secondary wiring 51so as to have the opening 52 a for revealing the electrode pad 51 aformed with the secondary wiring 51.

[0104] Thus, it is possible to flexibly vary a pattern of the secondarywiring 51 and a layout of the opening 52 a on the insulating layer 52,thereby easily enabling flip chip connection on a substrate or in thesemiconductor device.

[0105] Further, in the semiconductor chip 50 of the present embodiment,the shielding layer 4 is electrically connected via the secondary wiring51 to the electrode pad 2 as a ground terminal of a main body of thesemiconductor element. Thus, it is possible to achieve increased effectof preventing the electromagnetic waves, compared with a case where theshielding layer 4 is merely provided. Namely, even though a metalconductor has a characteristic to reflect electromagnetic waves, a smallamount of electromagnetic waves transmit the metal conductor. Thus, byelectrically connecting the shielding layer 4 with the ground terminal,most of the transmitted electromagnetic waves flow through the metalconductor as electric current, and are earthed.

[0106] Further, in the semiconductor chip 50 of the present embodiment,the secondary wiring 51 is further coated with the insulating layer 52.

[0107] This prevents short-circuiting with respect to other componentsand wiring in the device. Further, the insulating layer 52 protects thesecondary wiring 51, thus having an effect of preventing corrosion andphysical damages, etc. of the secondary wiring 51.

[0108] A method for manufacturing the semiconductor chip 50 of thepresent embodiment may be arranged so as to have the steps of (1)forming the secondary wiring 51 whose one end is electrically connectedto the electrode pads 2 provided on a front face of a wafer on which anelement circuit, the electrode pads 2, and the scribe lines 21 that areformed so as to surround the element circuit and the electrode pads 2are formed, respectively; (2) forming the insulating layer 52 so as tohave the opening 52 a on the secondary wiring 51; (3) fixing the jig 31on the front face of the wafer; (4) forming a groove along each of thescribe lines 21 on a back face which is on a back side of the waferfront face; (5) forming the shielding layer 4 so as to shieldelectromagnetic waves on the wafer back face having the groove and on aconcave portion of the groove; and (6) removing the jig 31 fixed on thewafer front face.

[0109] As a result, it is possible to provide a method for manufacturingthe semiconductor element 50 of the electromagnetic wave shielding type,in which a pattern of the secondary wiring 51 and a layout of theopening 52 a on the insulating layer 52 can be flexibly varied.

[0110] [Third Embodiment]

[0111] The following will explain a further embodiment of the presentinvention with reference to FIGS. 14, 15, and 16(a) to 16(d). For easeof explanation, members having the same functions as those shown in thedrawings pertaining to the first and second embodiments above will begiven the same reference symbols, and explanation thereof will beomitted here.

[0112] In the present embodiment, explained is a semiconductor chip of ashielding type in which a shielding layer is also formed on a front faceside of a semiconductor chip (semiconductor element).

[0113] In this semiconductor chip 60, the passivation film 3 is providedon a chip front face 60 a that has an element circuit (not shown). Thepassivation film 3 has the opening 3 a only at a portion on theelectrode pad 2.

[0114] In the present embodiment, as in Second Embodiment, the electrodepad 2 is electrically connected to one end of the secondary wiring 51,and an insulating layer 52 is formed thereon so as to have an opening 52a. A taper is formed on a chip side face 60 c of the semiconductor chip60, and the shielding layer 4 is formed on a chip back face 60 b and onthe chip side face 60 c.

[0115] When the shielding layer 4 is made of a conductive material, thesecondary wiring 51 is electrically connected to the electrode pad 2which is a ground terminal, and to the shielding layer 4. Further,another end of the secondary wiring 51 is revealed at the opening 52 aon the insulating layer 52. Further, the shielding layer 4 iselectrically connected to a shielding layer 64 on the circuit formedsurface of the semiconductor chip 60. As described above, in the presentembodiment, the shielding layer 64 is also formed on the insulatinglayer 52 on a side of the chip front face 60 a.

[0116] Further, in the present embodiment, a surface of the shieldinglayer 4 is coated with an insulating layer 62, and a surface of theshielding layer 64 is coated with an insulating layer 63. The insulatinglayers 62 and 63 are formed to protect the shielding layers 4 and 64,and to prevent short-circuiting, etc. with respect to other mountedcomponents, etc.

[0117] Incidentally, in the present embodiment, the shielding layers 4and 64 are made of a conductive material, but the material is notlimited to this. The shielding layers 4 and 64 may be made of anelectromagnetic wave absorbing material. In this case, as shown in FIG.15, it is not required to connect the electrode pad 2 as the groundterminal with the shielding layer 4. Further, the shielding layers 4 and64 themselves have insulating properties, thereby eliminating the needfor the insulating layers 52, 62, and 63 as the foundation andsurface-covering layers. Thus, it is possible to obtain thesemiconductor chip 60 having an electromagnetic wave shielding structureeasier, compared to a case where the shielding layer 4 made of aconductive material is used.

[0118] Next, a method for manufacturing the semiconductor chip 60 of thepresent embodiment will be explained with reference to FIGS. 16(a)through 16(d).

[0119] Note that, the steps explained in Second Embodiment aresubstantially the same as those in the manufacturing method of thepresent semiconductor chip 60, and thus only different steps will beexplained here.

[0120] In the present embodiment, as shown in FIG. 11(e), the insulatinglayer 52 is formed to protect the secondary wiring 51. Further, theinsulating layer 52 is formed in such a method that patterning forms anopening at a desired portion on the scribe lines 21 and on the secondarywiring 51, and then heat treatment is applied for curing.

[0121] Following this, in the present embodiment, as shown in FIG.16(a), after Ti—W and Au as metal thin films are formed by sputtering soas to respectively have a thickness of approximately 0.1 μm, a resist 61is formed on an entire surface of the element formed surface (not shown)of the wafer 20, and then photolithography is carried out so as to forman opening at a portion where the shielding layer 64 is to be formed.

[0122] Next, as shown in FIG. 16(b), Au is formed to have a totalthickness of 1 μm by an electrolytic plating method. If it is necessaryto form Au thicker, a time for plating may be increased. Further, theshielding layer 64 may be formed using a conductive material other thanAu and, for example, other metal materials such as Cu. In this case, Cuis formed by sputtering. Note that, when it is necessary to form Cuthicker, various methods may be employed such that Cu is further formedby electrolytic plating.

[0123] Next, as shown in FIG. 16(c), the resist 61 is separated using asolvent such as acetone, as in the case with the resist 53. After theresist 61 is separated, the Au and Ti—W metal thin films formed bysputtering, which become unnecessary, are sequentially removed by wetetching using the Au that is formed by electrolytic plating as a mask.

[0124] Next, as shown in FIG. 16(d), the insulating layer 63 is furtherformed on the shielding layer 64. Photosensitive resin varnish is usedas a material for forming the insulating layer 63. The photosensitiveresin varnish is applied and formed into a film, and thenphotolithography is carried out for patterning. The patterning forms anopening 64 a at a desired portion on the scribe lines 21 and on thesecondary wiring 51, and then heat treatment is applied for curing.

[0125] The following steps are carried out in the same manner as inFIGS. 3(a) through 3(d) in First Embodiment, or FIGS. 12(a) through12(c), 13(a), and 13(b) in Second Embodiment.

[0126] Incidentally, in the present embodiment, when photosensitiveresin containing ferrite particles is used to form the shielding layer64 on the element formed surface, it is possible to form the opening byphotolithography after the pasting. By using resin as a binder having aspecific property, as described above, it is possible to improveefficiency in manufacturing steps. For example, when resin having highductility at heating is pasted on the chip side face 60 c and the chipback face 60 b of the semiconductor chip 60, the resin easily fits theindented surface, thereby preventing the inclusion of bubbles.

[0127] As described above, in the semiconductor chip 60 of the presentembodiment, when the shielding layer 4 is made of a conductive material,the chip front face 60 a is also coated with the shielding layer 64 forshielding electromagnetic waves. Thus, it is possible to achieve anincreased effect of blocking electromagnetic waves and light, comparedwith a case where the shielding layer 4 covers only the chip back face60 b and chip side face 60 c of the semiconductor chip 60. As a result,it is possible to further prevent the generation of noise and theoccurrence of a malfunction.

[0128] Further, the semiconductor chip 60 of the present embodiment maybe so arranged that the shielding layer 4 is made of an electromagneticwave absorbing material that absorbs electromagnetic waves. Thiseliminates the influence of reflected electromagnetic waves. Further,since the electromagnetic wave absorbing material generally has aninsulating property, there is no need to form an insulating layer as thefoundation layer of the shielding layer 4. This also preventsshort-circuiting with respect to other components and wiring in thedevice.

[0129] Further, in the semiconductor chip 60 of the present embodiment,when the shielding layer 4 is made of an electromagnetic wave absorbingmaterial, the chip front face 60 a may be also coated with anelectromagnetic wave absorbing material. Thus, it is possible to achievean increased effect of blocking electromagnetic waves and light,compared with a case where the shielding layer 4 covers only the chipback face 60 b and the chip side face 60 c of the semiconductor chip 60.As a result, it is possible to further prevent the generation of noiseand the occurrence of a malfunction.

[0130] [Fourth Embodiment]

[0131] The following will explain yet another embodiment of the presentinvention with reference to FIGS. 17 and 18. For ease of explanation,members having the same functions as those shown in the drawingspertaining to the first through third embodiments above will be giventhe same reference symbols, and explanation thereof will be omittedhere.

[0132] In the present embodiment, explained are examples where asemiconductor chip of the electromagnetic wave shielding type is appliedto various types of semiconductor devices.

[0133] First, as shown in FIG. 17, a semiconductor device 70 is soarranged that, in the semiconductor chip 60 having the electromagneticwave shielding structure as shown in FIG. 14 in Third Embodiment, anexternal connecting terminal 71 is formed on the secondary wiring 51that is revealed at the opening on the insulating layer 63.

[0134] The external connecting terminal 71 may be formed in such amethod that, after flux is applied on the opening on the insulatinglayer 63, a solder ball of Sn—Ag, etc. is mounted by a ball mountingdevice, and a semispherical bump is obtained through a reflow oven inwhich heat treatment can be carried out in an atmosphere of N₂.

[0135] By arranging the secondary wiring 51 to include Au, Ni, and Cusequentially from the outermost layer, during the heat treatment by thereflow oven, Au facilitates solder wetting so that Ni is alloyed andelectrically connected with Sn in the solder. Note that, incross-sectional views of FIG. 17, two external connecting terminals 71are shown. The external connecting terminal 71 shown on the right sideis electrically connected via the secondary wiring 51 with the electrodepad 2 as the ground terminal, and is electrically connected to both theshielding layers 64. When the external connecting terminal 71 iselectrically connected to an earthed terminal on a substrate, increasedeffect of shielding electromagnetic waves can be attained.

[0136] On the other hand, as shown in FIG. 18, a semiconductor device 80is composed of the semiconductor chip 1 of the shielding type as shownin FIG. 1 in First Embodiment. In the semiconductor device 80, theelectrode pad 2 revealed at the opening 3 a on the passivation film 3 iselectrically connected via a bump 81 to wiring 83 on a wiring substrate(substrate) 82, and the wiring 83 is electrically connected to theexternal connecting terminal 71. Between the semiconductor chip 1 andthe wiring substrate 82, an anisotropic conductive film 84, in whichresin contains Ni particles, etc., is provided. By applying thermocompression bonding, the anisotropic conductive film 84 fixes thesemiconductor chip 1 onto the wiring substrate 82, and the Ni particleswedge both the bump 81 and the wiring 83 so as to electrically connectthem. When the electrode pad 2 is made of Al, Au is frequently used as abump material, and the bump may be an electrolytic plating bump, anelectroless plating bump, a wire bump formed with Au wire, and otherbumps. Sealing resin 85 is formed by transfer molding.

[0137] Incidentally, the semiconductor chips 1, 50, and 60 as have beenexplained can be applied to any semiconductor device.

[0138] As described above, the semiconductor device 70 of the presentembodiment is so arranged that the external connecting terminal 71 isdirectly formed on the semiconductor chip 60. Further, the semiconductordevice 80 is so arranged that the external connecting terminal 71 isindirectly formed on the semiconductor chip 1. Namely, the semiconductordevices 70 and 80 are composed of the semiconductor chips 1, 50 and 60of the electromagnetic wave shielding type.

[0139] With this, it becomes possible to provide the smallersemiconductor devices 70 and 80 compared with the conventionalsemiconductor device equipped with a shielding cap. This also eliminatesthe need for manufacturing the shielding cap variously in accordancewith different shapes and sizes of the semiconductor devices, so that apressing mold becomes unnecessary. This obviates the complexities ofmanufacturing and managing various kinds of shielding caps.

[0140] Further, in the semiconductor device 80 of the presentembodiment, any one of the semiconductor elements 1, 50 and 60 isprovided on the wiring substrate 82 having the wiring 83, the wiring 83of the wiring substrate 82 being electrically connected to the electrodepads 2 on the front face; the semiconductor chips 1, 50 and 60 beingsealed with the sealing resin 85; and the external connecting terminal71 being provided on the wiring substrate 82 on a back face of a surfacehaving the wiring 83 so as to be electrically connected to a part of thewiring 83.

[0141] Only by mounting a semiconductor element of the electromagneticwave shielding type instead of a conventional semiconductor element on aconventional semiconductor device of a resin sealing type, as describeabove, it is possible to obtain the semiconductor device 80 of theelectromagnetic wave shielding type. Namely, the semiconductor device 80of the shielding type has the same exterior appearance as theconventional semiconductor device. Thus, a conventional production linecan be used in an assembly process of the semiconductor device 80,thereby enabling substrate packaging without modifying a design of thesubstrate or changing a mounting jig.

[0142] As described above, a semiconductor element of the presentinvention, whose front face on which an element circuit is formed haselectrode pads and whose side face is provided between the front faceand a back face on a back side of the front face, is so arranged thatthe side face and the back face are coated with a shielding layer forshielding electromagnetic waves.

[0143] Namely, the conventional semiconductor device has a problem suchthat the entire size of the semiconductor device becomes very large,because the semiconductor device is covered with a shielding cap.

[0144] With the present invention, however, the side and back faces ofthe semiconductor element are coated with the shielding layer forshielding electromagnetic waves. In other words, the semiconductorelement is directly coated with the shielding layer.

[0145] As a result, it becomes possible to provide a semiconductorelement capable of being easily manufactured into a smallersemiconductor device compared with the conventional semiconductor deviceequipped with a shielding cap. This also eliminates the need formanufacturing the shielding cap variously in accordance with differentshapes and sizes of the semiconductor devices, so that a pressing moldbecomes unnecessary. This obviates the complexities of manufacturing andmanaging various kinds of shielding caps.

[0146] The semiconductor element of the present invention may be soarranged that a secondary wiring is further provided on the front faceso as to be electrically connected to the electrode pads; and aninsulating layer is provided on the secondary wiring so as to have anopening for revealing the electrode pads connected with the secondarywiring.

[0147] With this arrangement, a secondary wiring is further provided onthe front face of the element so as to be electrically connected to theelectrode pads. Further, an insulating layer is provided on thesecondary wiring so as to have an opening for revealing the electrodepads connected with the secondary wiring.

[0148] Thus, it is possible to flexibly vary a pattern of the secondarywiring and a layout of the opening on the insulating layer, therebyeasily enabling flip chip connection on a substrate or in thesemiconductor device.

[0149] Incidentally, the insulating layer is provided on the secondarywiring, thereby preventing short-circuiting with respect to othercomponents and wiring in the device. Further, the insulating layerprotects the secondary wiring, thus having an effect of preventingcorrosion and physical damages, etc. of the secondary wiring.

[0150] The semiconductor element of the present invention may be soarranged that the back face has a smaller area than the front face.

[0151] With this arrangement, the back face of the element has a smallerarea than the front face. Thus, when an insulating layer or a shieldinglayer is formed on the back and side faces of the semiconductor element,it is possible to uniformly form the layer to have almost the samethickness on the back and side faces of the semiconductor element.

[0152] The semiconductor element of the present invention may be soarranged that the shielding layer is made of a conductive material.

[0153] With this arrangement, the shielding layer is made of aconductive material. This prevents the entrance of electromagnetic wavesfrom the semiconductor element to the outside or from the outside to thesemiconductor element, thereby reducing the effects of noise, etc. Inaddition to electromagnetic waves, the shielding layer made of aconductive material also prevents the transmission of light, therebypreventing a malfunction due to a photovoltaic effect.

[0154] The semiconductor element of the present invention may be soarranged that the shielding layer is electrically connected to a groundterminal of a main body of the semiconductor element.

[0155] With this arrangement, the shielding layer is electricallyconnected to a ground terminal of a main body of the semiconductorelement. Thus, it is possible to achieve increased effect of preventingthe electromagnetic waves, compared with a case where the shieldinglayer is merely provided. Namely, even though a metal conductor has acharacteristic to reflect electromagnetic waves, a small amount ofelectromagnetic waves transmit the metal conductor. Thus, byelectrically connecting the shielding layer with the ground terminal,most of the transmitted electromagnetic waves flow through the metalconductor as electric current, and are earthed.

[0156] The semiconductor element of the present invention may be soarranged that the front face is coated with a shielding layer forshielding electromagnetic waves.

[0157] With this arrangement, when the shielding layer is made of aconductive material, the front face of the element is also coated with ashielding layer for shielding electromagnetic waves. Thus, it ispossible to achieve an increased effect of blocking electromagneticwaves and light, compared with a case where the shielding layer coversonly the back and side faces of the semiconductor element.

[0158] As a result, it is possible to further prevent the generation ofnoise and the occurrence of a malfunction.

[0159] The semiconductor element of the present invention may be soarranged that the shielding layer is further coated with an insulatinglayer.

[0160] With this arrangement, the shielding layer is further coated withan insulating layer. This prevents short-circuiting with respect toother components and wiring in the device. Further, the insulating layerprotects the shielding layer, thus having an effect of preventingcorrosion and physical damages, etc. of the shielding layer.

[0161] The semiconductor element of the present invention may be soarranged that the shielding layer is made of an electromagnetic waveabsorbing material.

[0162] With this arrangement, the shielding layer is made of anelectromagnetic wave absorbing material that absorbs electromagneticwaves. This eliminates the influence of reflected electromagnetic waves.Further, since the electromagnetic wave absorbing material generally hasan insulating property, there is no need to form an insulating layer asthe foundation and surface layers of the shielding layer. This alsoprevents short-circuiting with respect to other components and wiring inthe device. Further, in the semiconductor element in which a secondarywiring is further provided on the front face so as to be electricallyconnected to the electrode pads, and an insulating layer is provided onthe secondary wiring so as to have an opening for revealing theelectrode pads connected with the secondary wiring, there is no need toconnect the secondary wiring with the shielding layer.

[0163] The semiconductor element of the present invention may be soarranged that the front face is coated with an electromagnetic waveabsorbing material.

[0164] With this arrangement, when the shielding layer is made of anelectromagnetic wave absorbing material, the front face of the elementis also coated with an electromagnetic wave absorbing material. Thus, itis possible to achieve an increased effect of blocking electromagneticwaves and light, compared with a case where the shielding layer coversonly the back and side faces of the semiconductor element.

[0165] As a result, it is possible to further prevent the generation ofnoise and the occurrence of a malfunction.

[0166] A semiconductor device of the present invention is so arrangedthat an external connecting terminal is formed on the above-describedsemiconductor element.

[0167] With this arrangement, the semiconductor device is so arrangedthat an external connecting terminal is formed on the above-describedsemiconductor element. Namely, the semiconductor device is composed of asemiconductor element of the electromagnetic wave shielding type asarranged above.

[0168] With this, it becomes possible to provide a smaller semiconductordevice compared with the conventional semiconductor device equipped witha shielding cap. This also eliminates the need for manufacturing theshielding cap variously in accordance with different shapes and sizes ofthe semiconductor devices, so that a pressing mold becomes unnecessary.This obviates the complexities of manufacturing and managing variouskinds of shielding caps.

[0169] A semiconductor device of the present invention may be arrangedso as to include a substrate having wiring; and the above-describedsemiconductor element on the substrate, the wiring of the substratebeing electrically connected to the electrode pads on the front face;the semiconductor element being sealed with a resin; and an externalconnecting terminal being provided on the substrate on a back face of asurface having the wiring so as to be electrically connected to a partof the wiring.

[0170] With this arrangement, in the semiconductor device, theabove-described semiconductor element is provided on a substrate havingwiring, the wiring of the substrate being electrically connected to theelectrode pads on the front face; the semiconductor element being sealedwith a resin; and an electrode pad for an external connecting terminalbeing provided on the substrate on a back face of a surface having thewiring so as to be electrically connected to a part of the wiring.

[0171] Only by mounting a semiconductor element of the electromagneticwave shielding type instead of a conventional semiconductor element on aconventional semiconductor device of a resin sealing type, as describeabove, it is possible to obtain a semiconductor device of theelectromagnetic wave shielding type. Namely, the semiconductor device ofthe shielding type has the same exterior appearance as the conventionalsemiconductor device. Thus, a conventional production line can be usedin an assembly process of the semiconductor device, thereby enablingsubstrate packaging without modifying a design of the substrate orchanging a mounting jig.

[0172] A method for manufacturing a semiconductor element of the presentinvention is arranged so as to have the steps of (1) fixing a sheet orplate material on a front face of a wafer on which an element circuit,electrode pads, and a cutting line that is formed so as to surround theelement circuit and the electrode pads are formed, respectively; (2)forming a groove along the cutting line on a back face which is on aback side of the wafer front face; (3) forming a shielding layer so asto shield electromagnetic waves on the wafer back face having the grooveand on a concave portion of the groove; and (4) removing the sheet orplate material fixed on the wafer front face, the steps (1) through (4)being processed in this order.

[0173] With this method, when manufacturing the semiconductor element,first, (1) a sheet or plate material is fixed on a front face of a waferon which an element circuit, electrode pads, and a cutting line that isformed so as to surround the element circuit and the electrode pads areformed, respectively. Next, (2) a groove is formed along the cuttingline on a back face which is on a back side of the wafer front face.Then, (3) a shielding layer for shielding electromagnetic waves isformed on the wafer back face having the groove and on a concave portionof the groove. After this, (4) the sheet or plate material fixed on thewafer front face is removed.

[0174] With this, it is possible to provide a method for manufacturing asemiconductor element whose back and side faces have the electromagneticwave shielding structure.

[0175] A method for manufacturing a semiconductor element of the presentinvention may be arranged so as to have the steps of (1) forming asecondary wiring whose one end is electrically connected to electrodepads provided on a front face of a wafer on which an element circuit,the electrode pads, and a cutting line that is formed so as to surroundthe element circuit and the electrode pads are formed, respectively; (2)forming an insulating layer so as to have an opening on the secondarywiring; (3) fixing a sheet or plate material on the front face of thewafer; (4) forming a groove along the cutting line on a back face whichis on a back side of the wafer front face; (5) forming a shielding layerso as to shield electromagnetic waves on the wafer back face having thegroove and on a concave portion of the groove; and (6) removing thesheet or plate material fixed on the wafer front face, the steps (1)through (6) being processed in this order.

[0176] With this method, when manufacturing the semiconductor element,first, (1) a secondary wiring is formed, whose one end is electricallyconnected to electrode pads provided on a front face of a wafer on whichan element circuit, the electrode pads, and a cutting line that isformed so as to surround the element circuit and the electrode pads areformed, respectively. Next, (2) an insulating layer is formed so as tohave an opening on the secondary wiring, Then, (3) a sheet or platematerial is fixed on the front face of the wafer. Following this, (4) agroove is formed along the cutting line on a back face which is on aback side of the wafer front face.

[0177] Further, (5) a shielding layer for shielding electromagneticwaves is formed on the wafer back face having the groove and on aconcave portion of the groove. After this, (6) the sheet or platematerial fixed on the wafer front face is removed.

[0178] As a result, it is possible to provide a method for manufacturinga semiconductor element having the electromagnetic wave shieldingstructure, in which a pattern of the secondary wiring and a layout ofopening on the insulating layer can be flexibly varied.

[0179] The method for manufacturing the semiconductor element of thepresent invention may be so arranged that a taper is formed so that agroove has a wider width on a side of the back face than on a side ofthe front face, in the step of forming a groove along the cutting lineon the back face of the wafer.

[0180] With this arrangement, in the step of forming a groove along thecutting line on the back face of the wafer, a taper is formed so that agroove has a wider width on a side of the back face than on a side ofthe front face.

[0181] With this, when an insulating layer or a shielding layer isformed on the back and side faces of the semiconductor element, thelayer is uniformly formed to have almost the same thickness on the backand side faces. Thus, it is possible to provide a high-qualitysemiconductor element of the electromagnetic wave shielding type.

[0182] The invention being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art intended tobe included within the scope of the following claims.

What is claimed is:
 1. A semiconductor element, whose front face onwhich an element circuit is formed has electrode pads and whose sideface is provided between said front face and a back face on a back sideof said front face, wherein: said side face and said back face arecoated with a shielding layer for shielding electromagnetic waves. 2.The semiconductor element as set forth in claim 1, wherein: said backface has a smaller area than said front face.
 3. The semiconductorelement as set forth in claim 1, wherein: said shielding layer is madeof an electromagnetic wave absorbing material.
 4. The semiconductorelement as set forth in claim 3, wherein: said front face is coated withan electromagnetic wave absorbing material.
 5. The semiconductor elementas set forth in claim 4, wherein: the electromagnetic wave absorbingmaterial with which said front face is coated is a photosensitive resin.6. The semiconductor element as set forth in claim 1, wherein: saidshielding layer is made of a conductive material.
 7. The semiconductorelement as set forth in claim 6, wherein: the conductive material is Au.8. The semiconductor element as set forth in claim 6, wherein: theconductive material is Cu.
 9. The semiconductor element as set forth inclaim 6, wherein: said shielding layer is electrically connected to aground terminal of a main body of said semiconductor element.
 10. Thesemiconductor element as set forth in claim 6, wherein: said front faceis coated with a shielding layer for shielding electromagnetic waves.11. The semiconductor element as set forth in claim 6, wherein: saidshielding layer is further coated with an insulating layer.
 12. Thesemiconductor element as set forth in claim 1, wherein: a secondarywiring is further provided on said front face so as to be electricallyconnected to the electrode pads; and an insulating layer is provided onsaid secondary wiring so as to have an opening for revealing theelectrode pads connected with said secondary wiring.
 13. Thesemiconductor element as set forth in claim 12, wherein: said shieldinglayer is made of an electromagnetic wave absorbing material.
 14. Thesemiconductor element as set forth in claim 12, wherein: said shieldinglayer is made of a conductive material.
 15. The semiconductor element asset forth in claim 14, wherein: said shielding layer is electricallyconnected to a ground terminal of a main body of said semiconductorelement.
 16. A semiconductor device, wherein: an external connectingterminal is formed on a semiconductor element, whose front face on whichan element circuit is formed has electrode pads and whose side face isprovided between said front face and a back face on a back side of saidfront face, said side face and said back face being coated with ashielding layer for shielding electromagnetic waves.
 17. Thesemiconductor device as set forth in claim 16, wherein said shieldinglayer of said semiconductor element is made of a conductive material andis connected to a ground terminal of a main body of said semiconductorelement, said external connecting terminal being electrically connectedto the ground terminal.
 18. A semiconductor device, comprising: asubstrate having wiring; and a semiconductor element on said substrate,whose front face on which an element circuit is formed has electrodepads and whose side face is provided between said front face and a backface on a back side of said front face, said side face and said backface being coated with a shielding layer for shielding electromagneticwaves, the wiring of the substrate being electrically connected to theelectrode pads on said front face; said semiconductor element beingsealed with a resin; and an external connecting terminal being providedon said substrate on a back face of a surface having the wiring so as tobe electrically connected to a part of the wiring.
 19. A method formanufacturing a semiconductor element, comprising the steps of: (1)fixing a sheet or plate material on a front face of a wafer on which anelement circuit, electrode pads, and a cutting line that is formed so asto surround the element circuit and the electrode pads are formed,respectively; (2) forming a groove along the cutting line on a back facewhich is on a back side of the wafer front face; (3) forming a shieldinglayer so as to shield electromagnetic waves on the wafer back facehaving the groove and on a concave portion of the groove; and (4)removing the sheet or plate material fixed on the wafer front face, saidsteps (1) through (4) being processed in this order.
 20. The method formanufacturing the semiconductor element as set forth in claim 19,further comprising the step of: polishing the back face of the wafer sothat the wafer has a thickness of not more than about 200 μm, beforesaid step (2).
 21. The method for manufacturing the semiconductorelement as set forth in claim 19, wherein: a taper is formed so that agroove has a wider width on a side of the back face than on a side ofthe front face, in said step (2).
 22. A method for manufacturing asemiconductor element, comprising the steps of: (1) forming a secondarywiring whose one end is electrically connected to electrode padsprovided on a front face of a wafer on which an element circuit, theelectrode pads, and a cutting line that is formed so as to surround theelement circuit and the electrode pads are formed, respectively; (2)forming an insulating layer so as to have an opening on said secondarywiring; (3) fixing a sheet or plate material on the front face of thewafer; (4) forming a groove along the cutting line on a back face whichis on a back side of the wafer front face; (5) forming a shielding layerso as to shield electromagnetic waves on the wafer back face having thegroove and on a concave portion of the groove; and (6) removing thesheet or plate material fixed on the wafer front face, said steps (1)through (6) being processed in this order.